opensearch-docs-cn/_security-plugin/access-control/document-level-security.md

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default Document-level security Access control 10

Document-level security

Document-level security lets you restrict a role to a subset of documents in an index. The easiest way to get started with document- and field-level security is open OpenSearch Dashboards and choose Security. Then choose Roles, create a new role, and review the Index permissions section.

Document- and field-level security screen in OpenSearch Dashboards

Simple roles

Document-level security uses the OpenSearch query DSL to define which documents a role grants access to. In OpenSearch Dashboards, choose an index pattern and provide a query in the Document level security section:

{
  "bool": {
    "must": {
      "match": {
        "genres": "Comedy"
      }
    }
  }
}

This query specifies that for the role to have access to a document, its genres field must include Comedy.

A typical request to the _search API includes { "query": { ... } } around the query, but in this case, you only need to specify the query itself.

In the REST API, you provide the query as a string, so you must escape your quotes. This role allows a user to read any document in any index with the field public set to true:

PUT _plugins/_security/api/roles/public_data
{
  "cluster_permissions": [
    "*"
  ],
  "index_permissions": [{
    "index_patterns": [
      "pub*"
    ],
    "dls": "{\"term\": { \"public\": true}}",
    "allowed_actions": [
      "read"
    ]
  }]
}

These queries can be as complex as you want, but we recommend keeping them simple to minimize the performance impact that the document-level security feature has on the cluster. {: .warning }

Parameter substitution

A number of variables exist that you can use to enforce rules based on the properties of a user. For example, ${user.name} is replaced with the name of the current user.

This rule allows a user to read any document where the username is a value of the readable_by field:

PUT _plugins/_security/api/roles/user_data
{
  "cluster_permissions": [
    "*"
  ],
  "index_permissions": [{
    "index_patterns": [
      "pub*"
    ],
    "dls": "{\"term\": { \"readable_by\": \"${user.name}\"}}",
    "allowed_actions": [
      "read"
    ]
  }]
}

This table lists substitutions.

Term Replaced with
${user.name} Username.
${user.roles} A comma-separated, quoted list of user roles.
${attr.<TYPE>.<NAME>} An attribute with name <NAME> defined for a user. <TYPE> is internal, jwt, proxy or ldap

Attribute-based security

You can use roles and parameter substitution with the terms_set query to enable attribute-based security.

Note that the security_attributes of the index need to be of type keyword.

User definition

PUT _plugins/_security/api/internalusers/user1
{
  "password": "asdf",
  "backend_roles": ["abac"],
  "attributes": {
    "permissions": "\"att1\", \"att2\", \"att3\""
  }
}

Role definition

PUT _plugins/_security/api/roles/abac
{
  "index_permissions": [{
    "index_patterns": [
      "*"
    ],
    "dls": "{\"terms_set\": {\"security_attributes\": {\"terms\": [${attr.internal.permissions}], \"minimum_should_match_script\": {\"source\": \"doc['security_attributes'].length\"}}}}",
    "allowed_actions": [
      "read"
    ]
  }]
}